A light emitting diode (LED) is one of light emitting devices that emit light when a current is applied. The LED may emit light with high efficiency at low voltage, thereby having an excellent effect in energy saving.
A nitride semiconductor has received a great interest in a development field of an optical device and a high-power electronic device due to high thermal stability and wide band gap energy thereof. In particular, an ultraviolet (UV) LED, a blue LED, a green LED, a red LED, and the like using the nitride semiconductor are commercialized and used widely.
The ultraviolet light emitting device (UV LED) is a light emitting device that emits light in a wavelength range of 200 to 400 nm. The UV LED is composed of a short wavelength and a long wavelength depending on an application. The short wavelength is used for sterilization or purification, and the long wavelength may be used in an exposure apparatus or a curing apparatus, etc. Particularly, a UVB of a wavelength range of 280 to 315 nm may be used for a medical, etc.
Recently, a UV LED of a UVB, which is used for a precision medical equipment and the like, is required to implement a target wavelength within 280 nm to 315 nm and a high efficiency UV LED capable of high current drive. Further, a light emitting module for a medical equipment is required to have a UV LED capable of reducing the number of light emitting devices, implementing uniformity of light of 70% or more and implementing a therapeutic wavelength band.